Burglar alarm switch



Jan. 11, 1938. J. PICKARD BURGLAR ALARM SWITCH Filed Ffb. l2, 193.5 2 Sheets-S1166?. l

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Inventor Attomey r Jan. 11, 1938. J. PxcKARD BURGLAR ALARM SWITCH Filed Feb. 12, 1935 Patented Jan. 11, 1938 UNITED STATES PATENT OFFICE 1 Claim.

The present invention appertains to new and useful improvements in switches especially adapted for use in burglar alarm apparatus.

The principal object of the invention is to provide a burglar alarm switch which is especially adapted for use in hotels and other public dwelling places.

Another important object of the invention is to provide a switch structure which can be conveniently installed for use in conjunction with burglar alarms without requiring alteration of the building construction.

Other objects of the invention are to provide a burglar alarm switch which will be comparatively simple in. construction, strong, durable, eilicient and reliable in use, compact, portable and which may be manufactured at low cost.

All of the foregoing and still further objects and advantages of the invention will become apparent from a study of the following specification, taken in connection with the accompanying drawings wherein like characters of reference designate corresponding parts throughout the several views, and wherein:-

Figure 1 is a view in front elevation of the door switch.

Figure 2 is a top plan View of the door switch.

Figure 3 is a view in rear elevation of the door switch.

Figure 4 is a vertical sectional view, taken substantially on the line 4--4 of Figure 1.

Figure 5 is a View in front elevation of the operating means for the door switch.

Figure 6 is a detail View in perspective of the rod constituting a part of the door switch operating means.

Referring particularly to Figures 1 to 4, inclu sive, of the drawings, it will be seen that the door unit I I includes a clamp which is designated gen- 40 erally by the reference numeral I8 which is adapted to be removably mounted on the door frame I9. The clamp I8 includes a pair of opposed, co-acting jaws 20 which are slidably connected with each other and which are adapted to 45 embrace the door frame I9 therebetween. As

best seen in Figure 3 of the drawings, the longitudinal portion of one of the jaws 20 is provided with inturned flanges 2I providing channels in which the other of said jaws is slidable. An elongated screw 22 is mounted in the opposed portions of the jaws 20 and provided with a wing nut 23 for clamping said jaws on the door frame I9. Mounted on the clamp I8 is a switch 24 which includes contacts 25 with which a pivoted blade 26 is engageable, said blade 26 being provided with a projection or handle 2'I on its free end portion.

One end portion of the clamp arm 29 is formed to provide a jaw 32 engageable with a door knob shank (not shown) and which coacts with a pivoted jaw 33 for securing said arm 29 in position. A screw 34 is mounted in the arm 29 and extends slidably through the pivoted jaw 33 and has threaded thereon a wing nut 35 for closing said pivoted jaw against the tension of a coil spring 36 which. is mounted on said screw 34. Rising from the upper end of the arm 29 is a reduced threaded shank 31 having mounted thereon a pair of washers 38 between which a rod 39 is adjustably secured by a wing nut 40 on said shank 31. The rod 39 is preferably formed from a single length of suitable wire and said rod has formed on one end thereof a vertically elongated loop 4I in which the handle or projection 21 of the switch 24 is engaged. At its other end, the rod 39 termie nates in a substantially U-shaped portion 42 (see Figure 6) which straddles the shank 31 and which is clamped between the washers 38. It may be well to here state that the switch 24 is secured on one of the jaws 20 of the clamp I8 by a bolt 43, the other jaw 20 having formed therein a slot 44 which accommodates said bolt and the securing nut thereon, as shown to advantage in Figure 3 of the drawings.

It is believed that the many advantages of a burglar alarm constructed in accordance with the present invention will be readily understood, and although a preferred embodiment of the invention is as illustrated and described, it is to be understood that changes in the details of construction and in the combination and arrangement of parts may be resorted to which will fall within the scope of the invention as claimed.

What is claimed is:-

A switch operator comprising a switch operating arm having an outstanding pintle, a door knob attaching clamp, said clamp consisting of an elongated member having a curved end portion, a leg pivotally secured at one end to the intermediate portion of the elongated member and having its opposite end portion curved and opposed to the curved end of the elongated member, a bolt and nut connecting the leg with the elongated member, a coiled compressible spring on the bolt having its ends impinging against the said elongated member and the leg, the upper end of the elongated member being provided with a threaded extension, a nut on the threaded extension, a connecting rod having a slotted end receiving the pintle on the switch arm, the other end of the rod being secured to the door knob clamp by the clamping action of the nut on the threaded extension.

JOSEPH PICKARD. 

